Button Stand/Stance - The placement of the top button on a two-button jacket or the middle button a three-button jacket. Mostly an aesthetic feature, though placing it too high or too low can affect the proportions of the jacket and it's silhouette.
Canvas/Canvassing - Canvas is the material that floats in between the chest panel and lining of a jacket. It adds heft, body, and shape to a jacket. It's traditionally made of a combination of horsehair, linen, and wool. Canvassing is the traditional way of constructing a jacket and has been replaced by the use of fusible materials in most of the suit and sport coat market.
Delaminating - Uncanvassed jackets are fused together using a polymer resin and steam. Dry cleaning employs solvents - chemical agents meant to desolve grease, which just so happens to be chemically similar to resin. After a garment has been sufficiently bathed in solvents, it is steamed at high temperatures, which - you guessed it - returns the resin back to it's goopy state. This causes the fusible material to separate from the fabric in unpredictable ways, which creates visible puckering/bubbles in the jacket. This unsightly condition is referred to as delamination.
Double-Breasted - a type of jacket that folds over itself and has two rows of buttons in various different arrangements. Usually peak lapeled.
Four-In-Hand - A type of necktie knot that is slightly asymmetrical and not as wide as the Windsor, the other most common knot. When taken off, a four-in-hand knot can be identified because it comes completely undone without any untying.
Fusing/Fusible - Fusing is a process of attaching a resin material with steam to the inside of a jacket to add heft, akin to a iron on patch. It was invented to save time and money in the 1970s and has proliferated the market since, replacing the traditional canvas method in most markets. Compared to canvas, it is lifeless, less breathable, less durable and has the tendency to delaminate.
Lapel - The folded over front piece running down the chest to the top button of the jacket that connects to the collar at the gorge (or in the case of shawl, becomes the collar). There are three main types: notch, peak, and shawl.
Memory - The relative ability of a fabric to bounce back to it's original woven form. Wool has good memory and is wrinkle resistant, while cotton has poor memory and will remain wrinkled until steamed or pressed.
Peak Lapel - The second most common lapel style after notch. Peak is associated with tuxedos and double breasted suits and sport coats and is traditionally considered to be more formal. As opposed to the notch lapel where the collar is cut at the same angle as the gorge seam, the peak lapel extends upwards and past the collar.
Shawl Collar - The most formal collar/lapel style, traditionally seen on tuxedos and dinner jackets. The main feature of the shawl collar is that the collar essentially becomes the lapel with no seam or gorge.
Soft shoulder - The type of shoulder padding has a significant effect on the overall look of a jacket. There are two basic categories of shoulder pad (and many variations): soft/Neapolitan shoulder and structured. The Neapolitan shoulder is a soft, natural shoulder with very little additional padding beyond the shoulder. As the name implies, it initially rose to popularity in southern Italy. Within the Neapolitan category, there are some manufacturers that create small micro-pleats around the circumference of the shoulder-armhole seam, called "spalla camicia", which loosely translates to "shirt shoulder." This method provides more movement and flexibility and can only be done by hand, so it is more rare. Most Ezra Paul ready-to-wear has Neapolitan shoulders with spalla camicia.
Spalla Camicia - An Italian term for the micro-pleated effect seen on some Neapolitan shoulders. Loosely translates to "shirt shoulder." The effect is created by cutting a larger sleeve head and attaching it to the smaller armhole, which requires that the additional fabric be gathered. This can only be done by hand by an experiences craftsman. This process allows a high-armholed, narrow-shouldered jacket to still be comfortable by adding mobility.
Structured shoulder - The type of shoulder padding has a significant effect on the overall look of a jacket. There are two basic categories of shoulder pad (and many variations): soft shouldered and structured. The structured shoulder creates a more pronounced, angular transition from the top of the shoulder to the sleeves. It is an aesthetic difference and is sometimes associated with dressier suits and jackets.
Surgeon's Sleeves/Function Buttonholes - Working buttons on a jacket. Not usually seen on ready-to-wear since it severely limits the ability to shorten or lengthen sleeves as the buttonholes are cut. Sometimes referred to as "surgeon's sleeves" because in the days-of-old surgeons needed the ability to roll up their sleeves for surgery. If your surgeon is rolling up his suit or sport coat sleeves, go to a different surgeon or demand his dry cleaning receipt.
Tenderloin - The tenderloin sits beneath the ribs, next to the backbone. It has two ends: the butt and the "tail". It's considered to be one of the most tender and best tasting cuts.
Vents - The opening (or lack thereof) in the back of a jacket. Either none, center, or side. I've hear various reasons why they exist and the least outlandish is for horseback riding. Center vent used to be the most common until the mid-aughts and since then side vents have become the most prevalent.
Windsor Knot - A type of necktie knot that is generally wider, symmetrical, and more triangular than the four-in-hand, the other common knot. The two major variations are the "Half Windsor" and the "Full Windsor", which are identical except that the full is wrapped around one extra time. When taken off, a Windsor knot can be identified by the need to untie it. You shouldn't tie a full Windsor knot unless you are selling cell phones, in which case it seems to be compulsory.